Indicator



Dec. 28, 1943.

E. G. LIN DER INDICATOR original Filed Jim@ 25, 1940 Ffa. 1'.'

nnnrmnnnnn Snnentor Ernest G.Linder Mum Patented Dec. 28, 1943 UNITE ENTOFFICE v INDICATGR Ernest G. Linder, Philadelphia, Pa., assignor toRadio Corporation of America, a corporation of Delaware Claims.

This invention relates to indicators, and more particularly to electricindicators especially useful in connection with short wave circuits, thepresent application being a division of my copending application, SerialNo. 342,236, filed June 25, 1940, now Patent No. 2,296,678, grantedSeptember 22, 1942.

In my aforesaid copending application, I have disclosed an improvedmicrowave signal generator to which is coupled a tunable transmissionline, and the .primary object of my present invention is to provide animproved measuring device especially suited for use with short Wavecircuits of this type to indicate power, current, etc.

Another object of my present invention is to provide an improvedmeasuring device as aforesaid which is simple in construction and highlyefcient in use.

In accordance with this invention, I provide a multi-section, ultra highfrequency transmission line one section of which is terminated by aheater to which the junction of a thermocouple is connected. This heaternot only acts as a heater for the thermocouple, but also as a couplingelement to a second section of the transmission line, the latterterminating in a suitable antenna or other load. Preferably, thethermocouple is positioned at right angles to the heater to minimizeinduced currents and it may be connected to a galvanometer or othersuitable indieating instrument. The heater and thermocouple are arrangedin an evacuated glass container or envelope having a plane end, theheater being placed parallel to and as close to this end of the envelopeas possible in order to permit close coupling between the sections ofthe line or to any other suitable external circuit.

The novel features that I consider characteristic of my invention areset forth with particularity in the appended claims. The inventionitself, however, both as to its organization and method oi operation, aswell as additional objects and advantages thereof, will best beunderstood from the following description of one embodiment thereof,when read in connection with the accompanying drawing in which Figure 1is la view, partly in section, showing an ultra high frequency systemembodying my present invention,

Figure 2 is a circuit diagram showing, in detail, the relation betweenthe heater and the thermocouple, on the one hand, and the sections ofthe transmission line on the other hand.

Figure 3 is a longitudinal section of a vacuum tube constructedaccording to my present invention, and

Figure 4 is a sectional view taken on the line IV-IV of Figure.

Referring more particularly to the drawing, wherein similar referencecharacters designate corresponding parts throughout, there is shown, inFigure 1, a shielding container I, .such as a metallic box, Within whichis mounted a source 3 of high frequency energy, such as a magnetronoscillator, the box or container having a removable end portion .or wall2 beyond whichv is a shielding compartment 4 in which the wall 2 isenclosed. A telescoping closure 5 is adjustable ,on the box I by meansof the screws 6 to adjust the shielding compartment 4 to minimizestanding waves therein, all as more fully sei'l forth in my aboveidentied copending application.

Mounted within the shielding box is a shielding cylinder 1 within whichis located an evacuated glass envelope 9, the envelope 9 containing lapair of conductors I la constituting one section of a transmission lineconnected to the oscillator 3 and terminating in a heater element I3which constitutes a terminating impedance therefor (see Figure 2). Onthe outside of the box I is a shielding can or the like I5 which carriestelescoping shielding cylinders I'I within which the conductors IIbconstituting a second section of the transmission line are carried, theinner end of the line section IIb being terminated by a short conductorI9. The line sections IIa and IIb constitute a tunable transmission linewhich may be tuned to resonance by means of a rack and gear arrangement20, `and the entire line may be moved by a rack and gear 2l to vary theoutput delivered to a dipole antenna 23 or other suitable load. Theattenuation ratio is indicated by a pointer 25 and a scale 2I. Theconductor I9 is disposed parallel to the heater I3, and the heater I3 isarranged in parallel relation with and as close to the at or plane end9m of the envelope 9 as possible so that close coupling may be obtainedbetween the line sections IIa and IIb.

A thermocouple 29 is mounted in the envelope 9 preferably at rightangles to the heater I3 to minimize induced currents, the thermocouple29 being secured to the mid-point of the heater I3 in any suitablemanner. A pair of conductors 3| connect the free ends of thethermocouple 29 to a suitable D. C. meter, such as a galvanometer G,which may be mounted on the closure 5 and which indicates the currentset up in the thermocouple by the heater I3. Thus, the heater I3 ciallysuited for use in connection with short-Y Wave circuits. Although I haveshown and de-v scribed but one embodiment of my invention, it

Will be apparent to those skilled in the art that.

many variations therein, as Well as other modiiications, are possible. Itherefore desire that my invention shall not be limited except insofaras is made necessary by the prior art and by the spirit of the appendedclaims.'Y

I claim as my invention:

1. A vacuum thermocouple mounted in an evacuated container having asubstantially plane end, said thermocouple having a heater elementparallel to and so closely adjacent to said plane end that said elementmay be disposed in sufficiently close proximity to another conductiveelement outside of said container for close coupling thereto.

2. In combination, an evacuated envelope having a substantially planeend, a heater element Within said envelope parallel to said plane endand in such close proximity thereto that said element may be disposed insufliciently close proximity to another conductive element outside ofsaid envelope for close coupling thereto, and a thermocouple Within saidenvelope also parallel With said plane end, said thermocouple extendingat right angles to said heater element and being secured to said heaterelement.

' the radio frequency current at the coupling point `of said lines.

.4. In an ultra high frequency generator, a source of radio frequencyenergy, a transmission line coupled to said source, a thermocouplehaving a heater element, said element constituting a terminatingimpedance for said line, a, second transmission line coupled to saidheater element, and means for adjusting the relative positions of saidelement and said second line to vary the coupling therebetween.

5. In an ultra high frequency signal generator, a source ofoscillations, a shielding container for said source, said containerhaving a removable end portion, a shielding compartment enclosing saidend portion, means for adjusting said shield-Y ing compartment tominimize standing Waves therein, a transmission line coupled to saidsource, a thermocouple having a heater element and a thermal junctionelement, said heater element being connected to the end of said line andconstituting the terminating impedance thereof, a second transmissionline coupled to said heater element for deriving output currents fromsaid source, and indicating means mounted in said shielding compartmentand connected to said thermal junction element.

ERNEST G. LINDlElR.

